Processing device for performing convolution operations

ABSTRACT

Systems and methods for performing convolution operations. An example processing system comprises: a processing core; and a convolver unit to apply a convolution filter to a plurality of input data elements represented by a two-dimensional array, the convolver unit comprising a plurality of multipliers coupled to two or more sets of latches, wherein each set of latches is to store a plurality of data elements of a respective one-dimensional section of the two-dimensional array.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 14/136,302 filed on Dec. 20, 2013, titled “Processing device for performing convolution operations,” the entire content of which is incorporated by reference herein.

TECHNICAL FIELD

The present disclosure is generally related to processing systems, and is specifically related to systems and methods for processing devices for performing convolution operations.

BACKGROUND

Convolutional Neuron Network (CNN) is a computational model which has gained popularity due to its power in solving human-computer interface problems such as image processing and analysis. The core of the CNN model is a multi-staged algorithm that applies a set of pre-defined functional transformations to a plurality of inputs (e.g., image pixels). The transformed data may then be fed into a neuron network for pattern recognition.

BRIEF DESCRIPTION OF THE DRAWINGS

The present disclosure is illustrated by way of examples, and not by way of limitation, and may be more fully understood with references to the following detailed description when considered in connection with the figures, in which:

FIG. 1 depicts a high-level component diagram of an example convolutional neuron network (CNN) system;

FIG. 2 depicts a high-level component diagram of an example deep convolutional network (DCN) system;

FIGS. 3A-3B schematically illustrate example processing devices, in accordance with one or more aspects of the present disclosure;

FIG. 4 schematically illustrates a convolution operation followed by a subsampling (pooling) operation which may be performed by a CNN system;

FIG. 5 depicts a high-level component diagram of an example convolution circuit, in accordance with one or more aspects of the present disclosure;

FIGS. 6A-6D schematically illustrate an example of operation of the convolution circuit, in accordance with one or more aspects of the present disclosure;

FIG. 7 depicts a high-level component diagram of an example convolution circuit, in accordance with one or more aspects of the present disclosure;

FIG. 8 schematically illustrates a plurality of convolution circuits interconnected with each other in a variety ways in order to perform convolution operations with convolution filters of different sizes, in accordance with one or more aspects of the present disclosure;

FIG. 9 depicts a flow diagram of an example method for write allocation by a two-level memory controller, in accordance with one or more aspects of the present disclosure;

FIG. 10 depicts a high-level component diagram of an example computer system, in accordance with one or more aspects of the present disclosure;

FIG. 11 depicts a block diagram of a processor, in accordance with one or more aspects of the present disclosure;

FIGS. 12a-12b schematically illustrates elements of a processor micro-architecture, in accordance with one or more aspects of the present disclosure;

FIG. 13 depicts a block diagram of an example computer system, in accordance with one or more aspects of the present disclosure;

FIG. 14 depicts a block diagram of an example system on a chip (SoC), in accordance with one or more aspects of the present disclosure;

FIG. 15 depicts a block diagram of an example computer system, in accordance with one or more aspects of the present disclosure; and

FIG. 16 depicts a block diagram of an example system on a chip (SoC), in accordance with one or more aspects of the present disclosure.

DETAILED DESCRIPTION

Image Signal Processors (ISPs) in mobile devices are responsible for handling increasingly larger images while maintaining or even reducing the power consumption by the processing devices. One of the most common operations performed by ISPs is the convolution operation that involves applying a filter to an input image to obtain an output image of an equal or smaller size. Convolution filters may be used for many different applications, ranging from image restoration and enhancement to feature detection.

Convolutional neuron network (CNN) systems are commonly composed of layers of three different types: convolution, pooling, and fully-connected neuron network. FIG. 1 schematically illustrates a CNN system that includes a convolution layer 102, an average pooling layer 104, and a fully-connected neuron network 106. In an illustrative example, the convolution layer may apply filter operations 108 to pixels of the input image 110. Filter operations 108 may be implemented as a convolution of a kernel over the entire image as illustratively shown in element 112, in which x_(i-1), x_(i) . . . represent inputs (or pixel values), and k_(j−1), k_(j), k_(j+1) represent parameters of the kernel. Results of the filter operations 108 may be summed together to provide an output from the convolution layer 102 to the next pooling layer 104. The pooling layer 104 may perform subsampling to transform the images 110 to reduced images 114. Subsampling operations may comprise averaging operations and/or maximum value computations. Element 116 of FIG. 1 illustrates an average of inputs x_(o), x_(i), x_(n). The output of the pooling layer 104 may be fed to the fully-connected neuron network 106 to perform pattern detections. The fully-connected neuron network 106 may apply a set of weights 118 in its inputs and accumulate a result as the output of the fully-connected neuron network layer 106.

In certain implementations, convolution and pooling layers may be applied to input data multiple times prior to the results being transmitted to the fully-connected layer. Thereafter, the final output value may be tested to determine whether a pattern has been recognized. In accordance with one or more aspects of the present disclosure, several convolution operations may be grouped together in batches that correspond to the size of the pooling sample, and performed by a processing system 300, as described in more details herein below.

Deep Convolutional Networks (DCNs) also make extensive use of two-dimensional convolutions. DCNs are biologically inspired algorithms that are gaining interest due to their applications in novel human-computer interfaces, suitable of improved user-experience. Various object recognition algorithms use DCNs to achieve recognition rates which are significantly better than other known algorithms. A DCN may comprise three types of layers: convolution layers, pooling/subsampling layers, and fully connected layers. FIG. 2 schematically illustrates a DCN system comprising a feature extraction (convolution and pooling) layer 210 and a classification (fully-connected) layer 220.

In certain DCN implementations, a pooling layer follows a convolution layer. Hence, in accordance with one or more aspects of the present disclosure, several convolution operations may be grouped together in batches that correspond to the size of the pooling sample, and performed by a processing system 300, as described in more details herein below.

Disclosed herein are processing devices and methods for efficiently performing two-dimensional convolution operations. In an illustrative example, the processing device may be implemented as a system-on-chip (SoC). Other implementations of the systems and methods described herein may be applicable to other types of integrated circuits and processing devices

Various aspects of the above referenced methods and systems are described in details herein below by way of examples, rather than by way of limitation. In the following description, numerous specific details are set forth, such as examples of specific types of processors and system configurations, specific hardware structures, specific architectural and micro architectural details, specific register configurations, specific instruction types, specific system components, specific measurements/heights, specific processor pipeline stages and operation in order to provide a thorough understanding of the present disclosure. It will be apparent, however, to one skilled in the art that these specific details need not be employed to practice the methods disclosed herein. In other instances, well known components or methods, such as specific and alternative processor architectures, specific logic circuits/code for described algorithms, specific firmware code, specific interconnect operation, specific logic configurations, specific manufacturing techniques and materials, specific compiler implementations, specific expression of algorithms in code, specific power down and gating techniques/logic and other specific operational details of computer system have not been described in detail in order to avoid unnecessarily obscuring the present disclosure.

The examples illustrating the present disclosure and accompanied drawings should not be construed in a limiting sense as they are merely intended to provide examples of implementations described herein rather than to provide an exhaustive list of all possible implementations. Although the below examples describe instruction handling and distribution in the context of execution units and logic circuits, other implementations of the systems and methods described herein can be accomplished by way of a data or instructions stored on a machine-readable, tangible medium, which when performed by a machine cause the machine to perform functions consistent with at least one embodiment described herein. In certain implementations, functions associated with examples described herein are embodied in machine-executable instructions. The instructions can be used to cause a general-purpose or special-purpose processor that executes the instructions to perform the methods described herein. Examples described herein may include a computer program product or software which may be implemented by a machine or computer-readable medium having stored thereon instructions which may be used to program a computer (or other electronic devices) to perform one or more operations according to the examples described herein. Alternatively, operations of systems and methods described herein may be performed by specific hardware components that contain fixed-function logic for performing the operations, or by any combination of programmed computer components and fixed-function hardware components.

Instructions used to program logic to perform the methods described herein can be stored within a memory in the system, such as DRAM, cache, flash memory, or other storage. Furthermore, the instructions can be distributed via a network or by way of other computer readable media. Thus a machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computer), but is not limited to, floppy diskettes, optical disks, Compact Disc, Read-Only Memory (CD-ROMs), and magneto-optical disks, Read-Only Memory (ROMs), Random Access Memory (RAM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), magnetic or optical cards, flash memory, or a tangible, machine-readable storage used in the transmission of information over the Internet via electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.). Accordingly, the computer-readable medium includes any type of tangible machine-readable medium suitable for storing or transmitting electronic instructions or information in a form readable by a machine (e.g., a computer).

In certain implementations, a processing device designed in accordance with one or more aspects of the present disclosure may be implemented as a system-on-a-chip (SoC). FIG. 3A illustrates an example processing device 300 comprising a processor block 302, a convolver unit 304, and a bus/fabric/interconnect system 306. The processor block 302 may further comprise one or more processing cores 312 to perform general purpose calculations. The processing cores may communicate with convolver unit 304 over bus 206. The convolver unit 304 may further comprise a plurality of convolution circuits 314 each of which may be configured to perform one or more types of calculations as described in more details herein below.

Alternatively, the convolver unit may be integrated with a processing core, as schematically illustrated by FIG. 3B. A processing device 308 may include a processor block 310 and a bus/fabric system 306 through which processor block 310 may communicate with other components of the SoC or peripheral devices that are off the SoC. Processor block 310 may further include one or more processing cores 312, a plurality of convolution circuits 314, and a bridge 315 to connect the cores with the convolution circuits.

Convolution circuits 314 may be interconnected to each other and to other circuitry in a variety of ways. In certain implementations, one or more outputs of one convolution circuit 314 may be connected to inputs of another convolution circuit 314 in order to minimize the external memory access operations, as described in more details herein below.

As a convolution operation typically comprises applying a filter to an input image to obtain an output image of an equal or smaller size, a convolver unit may comprise several multipliers, adders, and associated circuitry. Since there may be a significant overlap in the input data used to produce two neighboring output pixels, the convolver unit may be designed to optimize the memory access operations by employing a plurality of latches to store the data that has once been retrieved from the external memory for re-using in processing a plurality of neighboring pixels.

FIG. 4 schematically illustrates a convolution operation followed by a subsampling (pooling) operation which may be performed by a CNN system. As noted herein above, a convolution operation may involve applying a convolution filter 410 to an input image 420 to obtain an output image 430 of an equal or smaller size: Σd_(n-i),_(n-j)*w_(i,j) wherein d_(ij) represents an input pixel value, and w_(ij) represents a convolution filter element.

In a typical CNN design, several convolution operations may be followed by a pooling operation. The latter may involve averaging the values of several neighboring pixels: Σd_(i)/n, wherein n is the number of neighboring pixels to be averaged.

Thus, in certain implementations a convolution circuit 314 employed by a convolver unit 304 of FIG. 3 may be designed to perform a group of convolution operations corresponding to the size of the pooling sample, so that the group of convolution operations would be followed by a pooling operation, in order to optimize the number of external memory access operations. Convolution circuit 314 may employ a plurality of latches to store the data that has once been retrieved from the external memory for re-using in processing a plurality of neighboring pixels.

As noted herein above, convolution circuits 314 may be interconnected to each other and to other circuitry in a variety of ways. In an illustrative example, for a 4×4 convolution filter, four convolution circuits may be employed, each convolution circuit having four multipliers to multiply the respective convolution filter elements by the input image pixels. As schematically illustrated by FIG. 5, each convolution circuit 314 may comprise a plurality of multipliers M1, . . . , M4 designed to independently of each other (e.g., simultaneously) perform a plurality of multiplication operations of a plurality of input image pixels and the respective convolution kernel elements: I₁*F₁,I₂*F₂,I₃*F₃, and I₄*F₄, wherein I₁, . . . I₄ represent the input pixel values, and F₁, . . . , F₄ represent the convolution filter values.

Convolution circuit 314 may further comprise a plurality of adders A1, . . . , A3 designed to sum the multiplication results: I₁*F₁+I₂*F₂+I₃*F₃+I₄*F₄

Convolution circuit 314 may further comprise two or more latches for every multiplier, schematically referenced in FIG. 5 as C_(1.1), . . . , C_(4.1) and C_(1.2), . . . , C_(4.2) which may be employed to store the input pixel values which are to be re-used at subsequent iterations, as described in more details herein below. Each of the two group of latches C_(3.1) and C_(j.2) may be employed to store the pixel values for a row of pixels of the input image fragment, so that latches C_(j.1) store a first row of pixels and latches C_(j.2) store an adjacent row of pixels. Respective multiplexers MUX₁, . . . , MUX₄ may be controlled by an external clock signal to select the signal to be fed to the multiplies M₁, . . . , M₄ from the first row of latches C_(j.1), the second row of latches C_(j.2), or the input lines I_(j), as described in more details herein below.

Convolution circuit 314 may further comprise a pooling circuit including a latch TA and an adder A_(p) configured to perform a subsampling operation by averaging the results of several convolution operations. Latch TA may be configured to store the intermediate sum after each addition operation performed by adder A_(p). In certain implementations, the pooling circuit may further comprise a shifter (not shown in FIG. 5) configured to divide the result produced by adder A_(p) by the convolution filter size, or an additional adder (not shown) used to compare convolution results and perform maximum value pooling.

FIGS. 6A-6D schematically illustrate an example of operation of convolution circuit 314 in accordance with one or more aspects of the present disclosure. Convolution circuit 314 may comprise four multipliers M₁, . . . , M₄ employed to multiple input pixel values to the respective convolution filter elements. The multiplication results are added together by three adders A₁, . . . , A₃ and fed to the subsampling (pooling) circuit to be averaged and finally outputted to other circuitry.

As convolution circuit 314 is employed to process various sequences of pixels of the input image, in the following examples, the plurality of adjacent input image pixels that are being processed by the convolution circuit at any given time are referred to as being comprised by an imaginary “input window” of the convolution circuit.

In the initial iteration of the four-iteration cycle comprised by the illustrative example, convolution circuit 314 may input four neighboring pixels I₁, . . . , I₄ by accessing the external memory via the respective input lines, as schematically illustrated by FIG. 6A. The input pixel values may be sent to multipliers M₁, . . . , M₄, as well as stored by latches C_(3.2), . . . , C_(1.2) for re-use by a subsequent convolution operation: the value of I₄ may be stored in latch C_(3.2), the value of I₃ may be stored in latch C_(2.2), and the value of I₂ may be stored in latch C_(1.2). The input pixel values may be further sent to another calculation unit 314 via the respective output lines O₁, O₂, O₃, and O₄. The result of applying the convolution filter F₁, . . . , F₄ to the input pixels (I₁*F₁+I₂*F₂+I₃*F₃+I₄*F₄) may be stored in TA latch for a subsequent pooling operation.

In the next iteration, the imaginary input window of convolution circuit 314 may shift to the next row of the input image, in order to apply to convolution filter to the pixels I₅, . . . , I₈, as schematically illustrated by FIG. 6B. There is no need to retrieve the respective pixel values from the external memory, as those have already been received, over the input lines I_R₁, . . . , I_R₄, from another convolution circuit and stored in latches C_(1.1), . . . , C_(4.1) during the previous iteration, in parallel with retrieving from the external memory and processing I₁, . . . , I₄ input pixels. In the input image 610, pixels in rows 612, 614, and 616 are already present the convolution circuit laches, while pixels in row 618 will need to be retrieved from the external memory.

The result of applying the convolution filter F₁, . . . , F₄ to the input pixels (I₅*F₁+I₆*F₂+I₇*F₃+I₈*F₄) may be added to the intermediate sum stored in TA latch and stored in TA latch again for a subsequent pooling operation.

In the next iteration, the imaginary input window of convolution circuit 314 may shift back to the pervious row and further shift by one pixel position along the column of the input image, in order to apply to convolution filter to the pixels I₂, I₃, I₄, and I_(A), as schematically illustrated by FIG. 6C. Since the pixel values I₂, I₃, and I₄ have already been inputted and stored in the respective latches C_(3.2), C_(2.2), and C_(1.2) during the first iteration of the four-iteration cycle, the only value that is inputted at the current iteration is the value of I_(A) which is inputted via input line I₄ as well as stored by latch C_(3.2) for re-use by a subsequent convolution operation. The result of applying the convolution filter F₁, . . . , F₄ to the input pixels (I₂*F₁+I₃*F₂+I₄*F₃+I_(A)*F₄) may be added to the intermediate sum stored in TA latch and stored in TA latch again for a subsequent pooling operation.

In the final iteration of the cycle, the imaginary input window of convolution circuit 314 may again shift to the next row of the input image, in order to apply to convolution filter to the pixels I₆, I₇, I₈, and I_(B), as schematically illustrated by FIG. 6D. There is no need to retrieve the respective pixel values from the external memory, as those have already been received, over the input lines I_R₁, . . . , I_R₄, from another convolution circuit and stored in latches C_(1.1), . . . , C_(4.1) during the previous iteration. The result of applying the convolution filter F₁, . . . , F₄ to the input pixels (I₆*F₁+I₇*F₂+I₈*F₃+I_(B)*F₄) may be added to the intermediate sum stored in TA latch and the result of the pooling operation may be outputted by the adder A_(p).

In certain implementations, instead of inserting multiplexers at the latch inputs, pairs of latches C_(j.1) and C_(j.2) corresponding to the input pixels having the same column numbers in two adjacent rows of the input image, may be connected in series, as schematically illustrated by FIG. 7. Thus, in one clock cycle the value from the first latch C_(j.1) would be supplied to the multiplier M_(j), and in the next clock cycle the value from the second latch C_(j.2) would be supplied to the multiplier M_(j).

In accordance with one or more aspects of the present disclosure, a processing system (such as a system-on-chip) may comprise a plurality of convolution circuits 314 which may be interconnected with each other and with other circuitry in a variety ways in order to perform convolution operations with convolution filters of different sizes. FIGS. 8A-8C schematically illustrate some of the configurations that may be implemented using 16 units of four multiplies each. In an illustrative example, if a filter line fits into a single convolution circuit (i.e., if one dimension of the filter does not exceed the number of multipliers of the convolution circuit), a plurality of convolution circuits can be combined so that each circuit processes one line of the convolution filter, as schematically illustrated by FIG. 8A representing four full 4×4 convolvers. Alternatively, if one dimension of the filter exceeds the number of multipliers of a convolution circuit, the convolution circuits can be grouped, so that each group of circuits would process a single filter line, as schematically illustrated by FIG. 8B representing one full 8×8 convolver. Alternatively, if the full size of the filter exceeds the number of multipliers of all convolution circuits available within a single processing device, the convolution circuits can be combined together to process a single filter line, as schematically illustrated by FIG. 8C representing a single line of a 64×64 convolver.

FIG. 9 depicts a flow diagram of an example method for performing convolution operations, in accordance with one or more aspects of the present disclosure. Method 900 may be performed by a processing system that may comprise hardware (e.g., circuitry, dedicated logic, and/or programmable logic), software (e.g., instructions executable on a computer system to perform hardware simulation), or a combination thereof. Method 900 and/or each of its functions, routines, subroutines, or operations may be performed by one or more physical processors of the computer system executing the method. Two or more functions, routines, subroutines, or operations of method 900 may be performed in parallel or in an order which may differ from the order described above. In certain implementations, method 900 may be performed by the processing systems described herein.

Referring to FIG. 9, at block 910, the processing device implementing method 900 may set an initial position of an input window in a two-dimensional array of input data elements. As noted herein above, the term “input window” herein refers to the plurality of adjacent input image pixels that are being processed by a convolution circuit.

At block 920, the processing device may applying a convolution filter to a plurality of input data elements referenced by the input window, as described in more details herein above. As noted herein above, the input data elements may be retrieved from an external memory.

At block 930, the processing device may shift the input window, relatively to its initial position, by one or more positions along the first one-dimensional section of the two-dimensional array (e.g., one or more rows down relatively to the initial position).

At block 940, the processing device may apply the convolution filter to a plurality of input data elements referenced by the input window, as described in more details herein above. As noted herein above, the input data elements may be retrieved from a plurality of latches where the input data elements have been stored during the previous processing operation.

The operations referenced by blocks 930 and 940 may be repeated several times, depending on the chosen pooling sample size. The number of iterations may be equal to the pooling sample dimension reduced by one, e.g., for 3×3 pooling the operations referenced by blocks 930 and 940 will be repeated twice, for 4×4 pooling the operations referenced by blocks 930 and 940 will be repeated three times, etc.

At block 950, the processing device may shift the input window, relatively to the initial position, by one position along the second one-dimensional section of the two-dimensional array (e.g., one column to the right relatively to the initial position).

At block 960, the processing device may apply the convolution filter to a plurality of input data elements referenced by the input window, as described in more details herein above. As noted herein above, all but one input data elements may be retrieved from a plurality of latches where the input data elements have been stored during the previous processing operation.

At block 970, the processing device may shift the input window by one position along the first one-dimensional section of the two-dimensional array (e.g., one row down).

At block 980, the processing device may apply the convolution filter to a plurality of input data elements referenced by the input window, as described in more details herein above. As noted herein above, the input data elements may be retrieved from a plurality of latches where the input data elements have been stored during the previous processing operation.

The operations referenced by blocks 970 and 980 may be repeated several times, depending on the chosen pooling sample size. The number of iterations may be equal to the pooling sample dimension reduced by one, e.g., for 3×3 pooling the operations referenced by blocks 970 and 980 will be repeated twice, for 4×4 pooling the operations referenced by blocks 970 and 980 will be repeated three times, etc.

The operations referenced by blocks 950-980 may be repeated several times, depending on the chosen pooling sample size. The number of iterations may be equal to the pooling sample dimension reduced by one, e.g., for 3×3 pooling the operations referenced by blocks 950-980 will be repeated twice, for 4×4 pooling the operations referenced by blocks 950-980 will be repeated three times, etc.

Responsive to completing the operations described with references to block 980, the method may terminate.

The methods and systems described herein above may be implemented by computer system of various architectures, designs and configurations for laptops, desktops, handheld PCs, personal digital assistants, engineering workstations, servers, network devices, network hubs, switches, embedded processors, digital signal processors (DSPs), graphics devices, video game devices, set-top boxes, micro controllers, cell phones, portable media players, hand held devices, and various other electronic devices, are also suitable to implement the methods described herein. In general, a large variety of systems or electronic devices capable of incorporating a processor and/or other execution logic as disclosed herein are generally suitable for implementing the systems and methods described herein.

FIG. 10 depicts a high-level component diagram of one example of a computer system in accordance with one or more aspects of the present disclosure. A computer system 100 may include a processor 110 to employ execution units including logic to perform algorithms for processing data, in accordance with the embodiment described herein. System 100 is representative of processing systems based on the PENTIUM III™, PENTIUM 4™, Xeon™, Itanium, XScale™ and/or StrongARM™ microprocessors available from Intel Corporation of Santa Clara, Calif., although other systems (including PCs having other microprocessors, engineering workstations, set-top boxes and the like) may also be used. In one embodiment, sample system 100 executes a version of the WINDOWS™ operating system available from Microsoft Corporation of Redmond, Wash., although other operating systems (UNIX and Linux for example), embedded software, and/or graphical user interfaces, may also be used. Thus, embodiments described herein are not limited to any specific combination of hardware circuitry and software.

In an illustrative example, processor 110 includes one or more processing cores 111 each comprising one or more execution units 108 to implement an algorithm that is to perform at least one instruction. One embodiment may be described in the context of a single processor desktop or server system, but alternative embodiments may be included in a multiprocessor system. System 100 is an example of a ‘hub’ system architecture. The computer system 100 includes a processor 110 to process data signals. The processor 110, as one illustrative example, includes a complex instruction set computer (CISC) microprocessor, a reduced instruction set computing (RISC) microprocessor, a very long instruction word (VLIW) microprocessor, a processor implementing a combination of instruction sets, or any other processor device, such as a digital signal processor, for example. The processor 110 is coupled to a processor bus 110 that transmits data signals between the processor 110 and other components in the system 100. The elements of system 100 (e.g. graphics accelerator 112, memory controller hub 116, memory 120, I/O controller hub 124, wireless transceiver 126, Flash BIOS 128, Network controller 134, Audio controller 136, Serial expansion port 138, I/O controller 140, etc.) perform their conventional functions that are well known to those familiar with the art.

In one embodiment, the processor 110 includes a Level 1 (L1) internal cache. Depending on the architecture, the processor 110 may have a single internal cache or multiple levels of internal caches. Other embodiments include a combination of both internal and external caches depending on the particular implementation and needs. Register file 106 is to store different types of data in various registers including integer registers, floating point registers, vector registers, banked registers, shadow registers, checkpoint registers, status registers, and instruction pointer register.

Execution unit 108, including logic to perform integer and floating point operations, also resides in the processor 110. The processor 110, in one embodiment, includes a microcode (ucode) ROM to store microcode, which when executed, is to perform algorithms for certain macroinstructions or handle complex scenarios. Here, microcode is potentially updateable to handle logic bugs/fixes for processor 110. For one embodiment, execution unit 108 includes logic to handle a packed instruction set 109. By including the packed instruction set 109 in the instruction set of a general-purpose processor 110, along with associated circuitry to execute the instructions, the operations used by many multimedia applications may be performed using packed data in a general-purpose processor 110. Thus, many multimedia applications are accelerated and executed more efficiently by using the full width of a processor's data bus for performing operations on packed data. This potentially eliminates the need to transfer smaller units of data across the processor's data bus to perform one or more operations, one data element at a time. Alternate embodiments of an execution unit 108 may also be used in micro controllers, embedded processors, graphics devices, DSPs, and other types of logic circuits. In certain implementations, the processor 110 may further include a cache control logic 124, the functioning of which is described in details herein below.

System 100 includes a memory 120. Memory 120 includes a dynamic random access memory (DRAM) device, a static random access memory (SRAM) device, flash memory device, or other memory device. Memory 120 stores instructions 129 and/or data 123 represented by data signals that are to be executed by the processor 110. In certain implementations, instructions 129 may include instructions implementing method 900 for optimized write allocation, as described in more details herein above.

A system logic chip 116 is coupled to the processor bus 110 and memory 120. The system logic chip 116 in the illustrated embodiment is a memory controller hub (MCH). The processor 110 can communicate to the MCH 116 via a processor bus 110. The MCH 116 provides a high bandwidth memory path 118 to memory 120 for instruction and data storage and for storage of graphics commands, data and textures. The MCH 116 is to direct data signals between the processor 110, memory 120, and other components in the system 100 and to bridge the data signals between processor bus 110, memory 120, and system I/O 122. In some embodiments, the system logic chip 116 can provide a graphics port for coupling to a graphics controller 112. The MCH 116 is coupled to memory 120 through a memory interface 118. The graphics card 112 is coupled to the MCH 116 through an Accelerated Graphics Port (AGP) interconnect 114.

System 100 uses a proprietary hub interface bus 122 to couple the MCH 116 to the I/O controller hub (ICH) 130. The ICH 130 provides direct connections to some I/O devices via a local I/O bus. The local I/O bus is a high-speed I/O bus for connecting peripherals to the memory 120, chipset, and processor 110. Some examples are the audio controller, firmware hub (flash BIOS) 128, wireless transceiver 126, data storage 124, legacy I/O controller containing user input and keyboard interfaces, a serial expansion port such as Universal Serial Bus (USB), and a network controller 134. The data storage device 124 can comprise a hard disk drive, a floppy disk drive, a CD-ROM device, a flash memory device, or other mass storage device.

For another embodiment of a system, an instruction in accordance with one embodiment can be used with a system on a chip. One embodiment of a system on a chip comprises of a processor and a memory. The memory for one such system is a flash memory. The flash memory can be located on the same die as the processor and other system components. Additionally, other logic blocks such as a memory controller or graphics controller can also be located on a system on a chip.

FIG. 11 is a block diagram of the micro-architecture for a processor 200 that includes logic circuits to perform instructions in accordance with one or more aspects of the present disclosure. In some embodiments, an instruction in accordance with one embodiment can be implemented to operate on data elements having sizes of byte, word, doubleword, quadword, etc., as well as datatypes, such as single and double precision integer and floating point datatypes. In one embodiment the in-order front end 201 is the part of the processor 200 that fetches instructions to be executed and prepares them to be used later in the processor pipeline. The front end 201 may include several units. In one embodiment, the instruction prefetcher 226 fetches instructions from memory and feeds them to an instruction decoder 228 which in turn decodes or interprets them. For example, in one embodiment, the decoder decodes a received instruction into one or more operations called “micro-instructions” or “micro-operations” (also referred to as uops) that the machine can execute. In other embodiments, the decoder parses the instruction into an opcode and corresponding data and control fields that are used by the micro-architecture to perform operations in accordance with one embodiment. In one embodiment, the trace cache 230 takes decoded uops and assembles them into program ordered sequences or traces in the uop queue 234 for execution. When the trace cache 230 encounters a complex instruction, the microcode ROM 232 provides the uops needed to complete the operation.

Some instructions are converted into a single micro-op, whereas others need several micro-ops to complete the full operation. In one embodiment, if more than four micro-ops are needed to complete an instruction, the decoder 228 accesses the microcode ROM 232 to do the instruction. For one embodiment, an instruction can be decoded into a small number of micro ops for processing at the instruction decoder 228. In another embodiment, an instruction can be stored within the microcode ROM 232 should a number of micro-ops be needed to accomplish the operation. The trace cache 230 refers to an entry point programmable logic array (PLA) to determine a correct micro-instruction pointer for reading the micro-code sequences to complete one or more instructions in accordance with one embodiment from the micro-code ROM 232. After the microcode ROM 232 finishes sequencing micro-ops for an instruction, the front end 201 of the machine resumes fetching micro-ops from the trace cache 230.

The out-of-order execution engine 203 is where the instructions are prepared for execution. The out-of-order execution logic has a number of buffers to smooth out and re-order the flow of instructions to optimize performance as they go down the pipeline and get scheduled for execution. The allocator logic allocates the machine buffers and resources that each uop needs in order to execute. The register aliasing logic maps logical registers onto entries in a register file. The allocator also allocates an entry for each uop in one of the two uop queues, one for memory operations and one for non-memory operations, in front of the instruction schedulers: memory scheduler, fast scheduler 202, slow/general floating point scheduler 204, and simple floating point scheduler 206. The uop schedulers 202, 204, 206 determine when a uop is ready to execute based on the readiness of their dependent input register operand sources and the availability of the execution resources the uops need to complete their operation. The fast scheduler 202 of one embodiment can schedule on each half of the main clock cycle while the other schedulers can schedule once per main processor clock cycle. The schedulers arbitrate for the dispatch ports to schedule uops for execution.

Physical register files 208, 210 sit between the schedulers 202, 204, 206, and the execution units 212, 214, 216, 218, 220, 222, 224 in the execution block 211. There is a separate register file 208, 210 for integer and floating point operations, respectively. Each register file 208, 210, of one embodiment also includes a bypass network that can bypass or forward just completed results that have not yet been written into the register file to new dependent uops. The integer register file 208 and the floating point register file 210 are also capable of communicating data with the other. For one embodiment, the integer register file 208 is split into two separate register files, one register file for the low order 32 bits of data and a second register file for the high order 32 bits of data. The floating point register file 210 of one embodiment has 128 bit wide entries because floating point instructions typically have operands from 64 to 128 bits in width.

The execution block 211 contains the execution units 212, 214, 216, 218, 220, 222, 224, where the instructions are actually executed. This section includes the register files 208, 210, that store the integer and floating point data operand values that the micro-instructions need to execute. The processor 200 of one embodiment is comprised of a number of execution units: address generation unit (AGU) 212, AGU 214, fast ALU 216, fast ALU 218, slow ALU 220, floating point ALU 222, floating point move unit 224. For one embodiment, the floating point execution blocks 222, 224, execute floating point, MMX, SIMD, and SSE, or other operations. The floating point ALU 222 of one embodiment includes a 64 bit by 64 bit floating point divider to execute divide, square root, and remainder micro-ops. For systems and methods described herein, instructions involving a floating point value may be handled with the floating point hardware. In one embodiment, the ALU operations go to the high-speed ALU execution units 216, 218. The fast ALUs 216, 218, of one embodiment can execute fast operations with an effective latency of half a clock cycle. For one embodiment, most complex integer operations go to the slow ALU 220 as the slow ALU 220 includes integer execution hardware for long latency type of operations, such as a multiplier, shifts, flag logic, and branch processing. Memory load/store operations are executed by the AGUs 212, 214. For one embodiment, the integer ALUs 216, 218, 220 are described in the context of performing integer operations on 64 bit data operands. In alternative embodiments, the ALUs 216, 218, 220 can be implemented to support a variety of data bits including 16, 32, 128, 256, etc. Similarly, the floating point units 222, 224 can be implemented to support a range of operands having bits of various widths. For one embodiment, the floating point units 222, 224 can operate on 128 bits wide packed data operands in conjunction with SIMD and multimedia instructions.

In one embodiment, the uops schedulers 202, 204, 206 dispatch dependent operations before the parent load has finished executing. As uops are speculatively scheduled and executed in processor 200, the processor 200 also includes logic to handle memory misses. If a data load misses in the data cache, there can be dependent operations in flight in the pipeline that have left the scheduler with temporarily incorrect data. A replay mechanism tracks and re-executes instructions that use incorrect data. The dependent operations should be replayed and the independent ones are allowed to complete. The schedulers and replay mechanism of one embodiment of a processor are also designed to catch instruction sequences for text string comparison operations.

The term “registers” may refer to the on-board processor storage locations that are used as part of instructions to identify operands. In other words, registers may be those that are usable from the outside of the processor (from a programmer's perspective). However, the registers of an embodiment should not be limited in meaning to a particular type of circuit. Rather, a register of an embodiment is capable of storing and providing data, and performing the functions described herein. The registers described herein can be implemented by circuitry within a processor using any number of different techniques, such as dedicated physical registers, dynamically allocated physical registers using register aliasing, combinations of dedicated and dynamically allocated physical registers, etc. In one embodiment, integer registers store thirty-two bit integer data. A register file of one embodiment also contains eight multimedia SIMD registers for packed data. For the discussions below, the registers are understood to be data registers designed to hold packed data, such as 64 bits wide MMX registers (also referred to as ‘mm’ registers in some instances) in microprocessors enabled with the MMX™ technology from Intel Corporation of Santa Clara, Calif. These MMX registers, available in both integer and floating point forms, can operate with packed data elements that accompany SIMD and SSE instructions. Similarly, 128 bits wide XMM registers relating to SSE2, SSE3, SSE4, or beyond (referred to generically as “SSEx”) technology can also be used to hold such packed data operands. In one embodiment, in storing packed data and integer data, the registers do not need to differentiate between the two data types. In one embodiment, integer and floating point are either contained in the same register file or different register files. Furthermore, in one embodiment, floating point and integer data may be stored in different registers or the same registers.

FIGS. 12a-12b schematically illustrates elements of a processor micro-architecture, in accordance with one or more aspects of the present disclosure. In FIG. 12a , a processor pipeline 400 includes a fetch stage 402, a length decode stage 404, a decode stage 406, an allocation stage 408, a renaming stage 410, a scheduling (also known as a dispatch or issue) stage 412, a register read/memory read stage 414, an execute stage 416, a write back/memory write stage 418, an exception handling stage 422, and a commit stage 424.

In FIG. 12b , arrows denote a coupling between two or more units and the direction of the arrow indicates a direction of data flow between those units. FIG. 12b shows processor core 111 including a front end unit 430 coupled to an execution engine unit 450, and both are coupled to a memory unit 470.

The core 111 may be a reduced instruction set computing (RISC) core, a complex instruction set computing (CISC) core, a very long instruction word (VLIW) core, or a hybrid or alternative core type. As yet another option, the core 111 may be a special-purpose core, such as, for example, a network or communication core, compression engine, graphics core, or the like.

The front end unit 430 includes a branch prediction unit 432 coupled to an instruction cache unit 434, which is coupled to an instruction translation lookaside buffer (TLB) 436, which is coupled to an instruction fetch unit 438, which is coupled to a decode unit 440. The decode unit or decoder may decode instructions, and generate as an output one or more micro-operations, micro-code entry points, microinstructions, other instructions, or other control signals, which are decoded from, or which otherwise reflect, or are derived from, the original instructions. The decoder may be implemented using various different mechanisms. Examples of suitable mechanisms include, but are not limited to, look-up tables, hardware implementations, programmable logic arrays (PLAs), microcode read only memories (ROMs), etc. The instruction cache unit 434 is further coupled to a level 2 (L2) cache unit 476 in the memory unit 470. The decode unit 440 is coupled to a rename/allocator unit 452 in the execution engine unit 450.

The execution engine unit 450 includes the rename/allocator unit 452 coupled to a retirement unit 454 and a set of one or more scheduler unit(s) 456. The scheduler unit(s) 456 represents any number of different schedulers, including reservations stations, central instruction window, etc. The scheduler unit(s) 456 is coupled to the physical register file(s) unit(s) 458. Each of the physical register file(s) units 458 represents one or more physical register files, different ones of which store one or more different data types, such as scalar integer, scalar floating point, packed integer, packed floating point, vector integer, vector floating point, etc., status (e.g., an instruction pointer that is the address of the next instruction to be executed), etc. The physical register file(s) unit(s) 458 is overlapped by the retirement unit 454 to illustrate various ways in which register aliasing and out-of-order execution may be implemented (e.g., using a reorder buffer(s) and a retirement register file(s), using a future file(s), a history buffer(s), and a retirement register file(s); using a register maps and a pool of registers; etc.). Generally, the architectural registers are visible from the outside of the processor or from a programmer's perspective. The registers are not limited to any known particular type of circuit. Various different types of registers are suitable as long as they are capable of storing and providing data as described herein. Examples of suitable registers include, but are not limited to, dedicated physical registers, dynamically allocated physical registers using register aliasing, combinations of dedicated and dynamically allocated physical registers, etc. The retirement unit 454 and the physical register file(s) unit(s) 458 are coupled to the execution cluster(s) 460. The execution cluster(s) 460 includes a set of one or more execution units 162 and a set of one or more memory access units 464. The execution units 462 may perform various operations (e.g., shifts, addition, subtraction, multiplication) and on various types of data (e.g., scalar floating point, packed integer, packed floating point, vector integer, vector floating point). While some embodiments may include a number of execution units dedicated to specific functions or sets of functions, other embodiments may include one execution unit or multiple execution units that all perform all functions. The scheduler unit(s) 456, physical register file(s) unit(s) 458, and execution cluster(s) 460 are shown as being possibly plural because certain embodiments create separate pipelines for certain types of data/operations (e.g., a scalar integer pipeline, a scalar floating point/packed integer/packed floating point/vector integer/vector floating point pipeline, and/or a memory access pipeline that each have their own scheduler unit, physical register file(s) unit, and/or execution cluster—and in the case of a separate memory access pipeline, certain embodiments are implemented in which the execution cluster of this pipeline has the memory access unit(s) 464). It should also be understood that where separate pipelines are used, one or more of these pipelines may be out-of-order issue/execution and the rest in-order.

The set of memory access units 464 is coupled to the memory unit 470, which includes a data TLB unit 472 coupled to a data cache unit 474 coupled to a level 2 (L2) cache unit 476. In one exemplary embodiment, the memory access units 464 may include a load unit, a store address unit, and a store data unit, each of which is coupled to the data TLB unit 472 in the memory unit 470. The L2 cache unit 476 is coupled to one or more other levels of cache and eventually to a main memory.

By way of example, the exemplary register aliasing, out-of-order issue/execution core architecture may implement the pipeline 400 as follows: the instruction fetch 438 performs the fetch and length decoding stages 402 and 404; the decode unit 440 performs the decode stage 406; the rename/allocator unit 452 performs the allocation stage 408 and renaming stage 410; the scheduler unit(s) 456 performs the schedule stage 412; the physical register file(s) unit(s) 458 and the memory unit 470 perform the register read/memory read stage 414; the execution cluster 460 perform the execute stage 416; the memory unit 470 and the physical register file(s) unit(s) 458 perform the write back/memory write stage 418; various units may be involved in the exception handling stage 422; and the retirement unit 454 and the physical register file(s) unit(s) 458 perform the commit stage 424.

The core 111 may support one or more instructions sets (e.g., the x86 instruction set (with some extensions that have been added with newer versions); the MIPS instruction set of MIPS Technologies of Sunnyvale, Calif.; the ARM instruction set (with additional extensions such as NEON) of ARM Holdings of Sunnyvale, Calif.).

In certain implementations, the core may support multithreading (executing two or more parallel sets of operations or threads), and may do so in a variety of ways including time sliced multithreading, simultaneous multithreading (where a single physical core provides a logical core for each of the threads that physical core is simultaneously multithreading), or a combination thereof (e.g., time sliced fetching and decoding and simultaneous multithreading thereafter such as in the Intel® Hyperthreading technology).

While register aliasing is described in the context of out-of-order execution, it should be understood that register aliasing may be used in an in-order architecture. While the illustrated embodiment of the processor also includes a separate instruction and data cache units 434/474 and a shared L2 cache unit 476, alternative embodiments may have a single internal cache for both instructions and data, such as, for example, a Level 1 (L1) internal cache, or multiple levels of internal cache. In some embodiments, the system may include a combination of an internal cache and an external cache that is external to the core and/or the processor. Alternatively, all of the cache may be external to the core and/or the processor.

In certain implementations, processor core 111 may be designed as an out-of-order (OOO) core in order to improve the performance by executing instructions as soon as their operands become available, rather than in the program order. However, the performance benefit may be offset by a considerable increase in the power consumption. When multiple execution threads are available for the operating system to schedule, employing multiple in-order cores rather than large OOO cores may improve the energy consumption profile of the processor without compromising the overall performance. Thus, to improve the performance and energy consumption scalability of a processor, the latter may be designed to support a variable number of cores depending on the performance needs and the number of threads available to the operating system for scheduling.

FIG. 13 depicts a block diagram of an example computer system, in accordance with one or more aspects of the present disclosure. As shown in FIG. 13, multiprocessor system 700 is a point-to-point interconnect system, and includes a first processor 770 and a second processor 780 coupled via a point-to-point interconnect 750. Each of processors 770 and 780 may be some version of the processor 102 capable of performing return address verification, as described in more details herein above. While shown with only two processors 770, 780, it is to be understood that the scope of the present disclosure is not so limited. In other embodiments, one or more additional processors may be present in the example computer system.

Processors 770 and 780 are shown including integrated memory controller units 772 and 782, respectively. Processor 770 also includes as part of its bus controller units point-to-point (P-P) interfaces 776 and 778; similarly, second processor 780 includes P-P interfaces 786 and 788. Processors 770, 780 may exchange information via a point-to-point (P-P) interface 750 using P-P interface circuits 778, 788. As shown in FIG. 13, IMCs 772 and 782 couple the processors to respective memories, namely a memory 732 and a memory 734, which may be portions of main memory locally attached to the respective processors.

Processors 770, 780 may each exchange information with a chipset 790 via individual P-P interfaces 752, 754 using point to point interface circuits 776, 794, 786, 798. Chipset 790 may also exchange information with a high-performance graphics circuit 738 via a high-performance graphics interface 739.

A shared cache (not shown) may be included in either processor or outside of both processors, yet connected with the processors via P-P interconnect, such that either or both processors' local cache information may be stored in the shared cache if a processor is placed into a low power mode.

Chipset 790 may be coupled to a first bus 716 via an interface 796. In one embodiment, first bus 716 may be a Peripheral Component Interconnect (PCI) bus, or a bus such as a PCI Express bus or another third generation I/O interconnect bus, although the scope of the present disclosure is not so limited.

As shown in FIG. 13, various I/O devices 714 may be coupled to first bus 716, along with a bus bridge 718 which couples first bus 716 to a second bus 720. In one embodiment, second bus 720 may be a low pin count (LPC) bus. Various devices may be coupled to second bus 720 including, for example, a keyboard and/or mouse 722, communication devices 727 and a storage unit 728 such as a disk drive or other mass storage device which may include instructions/code and data 730, in one embodiment. Further, an audio I/O 724 may be coupled to second bus 720.

FIG. 14 depicts a block diagram of an example system on a chip (SoC), in accordance with one or more aspects of the present disclosure. The application processor 910 may be capable of performing return address verification, as described in more details herein above. As schematically illustrated by FIG. 14, interconnect unit(s) 902 may be coupled to: an application processor 910 which includes a set of one or more cores 902A-N and shared cache unit(s) 906; a system agent unit 910; a bus controller unit(s) 916; an integrated memory controller unit(s) 914; a set or one or more media processors 920 which may include integrated graphics logic 908, an image processor 924 for providing still and/or video camera functionality, an audio processor 926 for providing hardware audio acceleration, and a video processor 928 for providing video encode/decode acceleration; an static random access memory (SRAM) unit 930; a direct memory access (DMA) unit 932; and a display unit 940 for coupling to one or more external displays.

FIG. 15 depicts a block diagram of an example computer system, in accordance with one or more aspects of the present disclosure. Processor 1610 may be provided by some version of the processor 102 capable of performing return address verification, as described in more details herein above.

The system 1600 schematically illustrated by FIG. 15 may include any combination of components implemented as ICs, portions thereof, discrete electronic devices, or other modules, logic, hardware, software, firmware, or a combination thereof adapted in a computer system, or as components otherwise incorporated within a chassis of the computer system. The block diagram of FIG. 15 is intended to show a high level view of many components of the computer system. However, it is to be understood that some of the components shown may be omitted, additional components may be present, and different arrangement of the components shown may occur in other implementations.

Processor 1610 may be provided by a microprocessor, multi-core processor, multithreaded processor, an ultra low voltage processor, an embedded processor, or other known processing element. In the illustrated implementation, processor 1610 acts as a main processing unit and central hub for communication with many of the various components of the system 1600. As one example, processor 1600 may be implemented as a system on a chip (SoC). As a specific illustrative example, processor 1610 includes an Intel® Architecture Core™-based processor such as an i3, i5, i7 or another such processor available from Intel Corporation, Santa Clara, Calif.

Processor 1610 may communicate with a system memory 1615. In various implementations the individual memory devices may be of different package types such as single die package (SDP), dual die package (DDP) or quad die package (1P). These devices, in some implementations, may be directly soldered onto a motherboard to provide a lower profile solution, while in other implementations the devices may be configured as one or more memory modules that in turn couple to the motherboard by a given connector. Other memory implementations are possible, such as other types of memory modules, e.g., dual inline memory modules (DIMMs) of different varieties including but not limited to microDlMMs, MiniDIMMs. In one illustrative example, the memory may be sized between 2 GB and 16 GB, and may be configured as a DDR3LM package or an LPDDR2 or LPDDR3 memory that is soldered onto a motherboard via a ball grid array (BGA).

To provide for persistent storage of information such as data, applications, one or more operating systems and so forth, a mass storage 1620 may be also coupled to processor 1610. In certain implementations, to enable a thinner and lighter system design as well as to improve system responsiveness, the mass storage 1620 may be implemented via a SSD. In other implementations, the mass storage may primarily be provided by a hard disk drive (HDD) with a smaller amount of SSD storage to act as a SSD cache to enable non-volatile storage of context state and other such information during power down events so that a fast power up can occur on re-initiation of system activities.

Also shown in FIG. 15, a flash device 1622 may be coupled to processor 1610, e.g., via a serial peripheral interface (SPI). The flash device 1622 may provide for non-volatile storage of system software, including a basic input/output software (BIOS) as well as other firmware of the system.

In various implementations, the mass storage of the system may be provided by a SSD alone or as a disk, optical or other drive with an SSD cache. In some implementations, the mass storage may be provided by an SSD or as a HDD along with a restore (RST) cache module. The SSD cache may be configured as a single level cache (SLC) or multi-level cache (MLC) option to provide an appropriate level of responsiveness.

Various input/output (IO) devices may be present within system 1600, including, e.g., a display 1624 which may be provided by a high definition LCD or LED panel configured within a lid portion of the chassis. This display panel may also provide for a touch screen 1625 adapted externally over the display panel such that via a user's interaction with this touch screen, user inputs can be provided to the system to enable desired operations, e.g., with regard to the display of information, accessing of information and so forth. In certain implementations, display 1624 may be coupled to processor 1610 via a display interconnect that can be implemented as a high performance graphics interconnect. Touch screen 1625 may be coupled to processor 1610 via another interconnect, which in an embodiment can be an I2C interconnect. In addition to touch screen 1625, user input by way of touch can also occur via a touch pad 1630 which may be configured within the chassis and may also be coupled to the same I2C interconnect as touch screen 1625.

Various sensors may be present within the system and may be coupled to processor 1610 in different manners. Certain inertial and environmental sensors may couple to processor 1610 through a sensor hub 1640, e.g., via an I2C interconnect. These sensors may include an accelerometer 1641, an ambient light sensor (ALS) 1642, a compass 1643 and a gyroscope 1644. Other environmental sensors may include one or more thermal sensors 1646 which in some embodiments couple to processor 1610 via a system management bus (SMBus) bus. In certain implementations, one or more infrared or other heat sensing elements, or any other element for sensing the presence or movement of a user may be present.

Various peripheral devices may couple to processor 1610 via a low pin count (LPC) interconnect. In certain implementations, various components can be coupled through an embedded controller 1635. Such components can include a keyboard 1636 (e.g., coupled via a PS2 interface), a fan 1637, and a thermal sensor 1639. In some embodiments, touch pad 1630 may also couple to EC 1635 via a PS2 interface. In addition, a security processor such as a trusted platform module (TPM) 1638 in accordance with the Trusted Computing Group (TCG) TPM Specification Version 1.2, dated Oct. 2, 2003, may also couple to processor 1610 via this LPC interconnect.

In certain implementations, peripheral ports may include a high definition media interface (HDMI) connector (which can be of different form factors such as full size, mini or micro); one or more USB ports, such as full-size external ports in accordance with the Universal Serial Bus Revision 3.0 Specification (November 2008), with at least one powered for charging of USB devices (such as smartphones) when the system is in Connected Standby state and is plugged into AC wall power. In addition, one or more Thunderbolt™ ports can be provided. Other ports may include an externally accessible card reader such as a full size SD-XC card reader and/or a SIM card reader for WWAN (e.g., an 8 pin card reader). For audio, a 3.5 mm jack with stereo sound and microphone capability (e.g., combination functionality) can be present, with support for jack detection (e.g., headphone only support using microphone in the lid or headphone with microphone in cable). In some embodiments, this jack can be re-taskable between stereo headphone and stereo microphone input. Also, a power jack can be provided for coupling to an AC brick.

System 1600 can communicate with external devices in a variety of manners, including wirelessly. In the embodiment shown in FIG. 16, various wireless modules, each of which can correspond to a radio configured for a particular wireless communication protocol, are present. One manner for wireless communication in a short range such as a near field may be via a near field communication (NFC) unit 1645 which may communicate, in one embodiment with processor 1610 via an SMBus.

Additional wireless units can include other short range wireless engines including a WLAN unit 1650 and a Bluetooth unit 1652. Using WLAN unit 1650, WiFi™ communications in accordance with a given Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard can be realized, while via Bluetooth unit 1652, short range communications via a Bluetooth protocol can occur. These units may communicate with processor 1610 via, e.g., a USB link or a universal asynchronous receiver transmitter (UART) link. Or these units may couple to processor 1610 via an interconnect according to a Peripheral Component Interconnect Express™ (PCIe™) protocol, e.g., in accordance with the PCI Express™ Specification Base Specification version 3.0 (published Jan. 17, 2007), or another such protocol such as a serial data input/output (SDIO) standard. Of course, the actual physical connection between these peripheral devices, which may be configured on one or more add-in cards, can be by way of the NGFF connectors adapted to a motherboard.

In addition, wireless wide area communications, e.g., according to a cellular or other wireless wide area protocol, can occur via a WWAN unit 1656 which in turn may couple to a subscriber identity module (SIM) 1657. In addition, to enable receipt and use of location information, a GPS module 1655 may also be present.

To provide for audio inputs and outputs, an audio processor can be implemented via a digital signal processor (DSP) 1660, which may couple to processor 1610 via a high definition audio (HDA) link. Similarly, DSP 1660 may communicate with an integrated coder/decoder (CODEC) and amplifier 1662 that in turn may couple to output speakers 1663 which may be implemented within the chassis. Similarly, amplifier and CODEC 1662 can be coupled to receive audio inputs from a microphone 1665.

FIG. 16 depicts a block diagram of an example system on a chip (SoC), in accordance with one or more aspects of the present disclosure. As a specific illustrative example, SOC 1700 may be included in user equipment (UE). In one embodiment, UE refers to any device to be used by an end-user to communicate, such as a hand-held phone, smartphone, tablet, ultra-thin notebook, notebook with broadband adapter, or any other similar communication device. Often a UE connects to a base station or node, which potentially corresponds in nature to a mobile station (MS) in a GSM network.

As schematically illustrated by FIG. 16, SOC 1700 may include two cores. Cores 1706 and 1707 may be coupled to cache control 1708 that is associated with bus interface unit 1709 and L2 cache 1710 to communicate with other parts of system 1700. Interconnect 1710 may include an on-chip interconnect, such as an IOSF, AMBA, or other interconnect.

Interface 1710 may provide communication channels to the other components, such as a Subscriber Identity Module (SIM) 1730 to interface with a SIM card, a boot ROM 1735 to hold boot code for execution by cores 1706 and 1707 to initialize and boot SOC 1700, a SDRAM controller 1740 to interface with external memory (e.g., DRAM 1760), a flash controller 1745 to interface with non-volatile memory (e.g., flash 1765), a peripheral control 1550 (e.g., Serial Peripheral Interface) to interface with peripherals, video codecs 1720 and Video interface 1725 to display and receive input (e.g., touch enabled input), GPU 1715 to perform graphics related computations, etc. In addition, the system may comprise peripherals for communication, such as a Bluetooth module 1770, 3G modem 1775, GPS 1785, and WiFi 1785.

Other computer system designs and configurations may also be suitable to implement the systems and methods described herein. The following examples illustrate various implementations in accordance with one or more aspects of the present disclosure.

Example 1 is a processing system, comprising: a processing core; and a convolver unit to apply a convolution filter to a plurality of input data elements represented by a two-dimensional array, the convolver unit comprising a plurality of multipliers coupled to two or more sets of latches, wherein each set of latches is to store a plurality of data elements of a respective one-dimensional section of the two-dimensional array.

Example 3 is the processing system of Example 1, wherein the two or more sets of latches may be provided by a first set of latches and a second set of latches, wherein the first set of latches is to store a first plurality of data elements of a first one-dimensional section of the two-dimensional array and the second set of latches is to store a second plurality of data elements of a second one-dimensional section of the two-dimensional array.

Example 3 is the processing system of Example 1, wherein the first one-dimensional section may be provided by a first row the and second one-dimensional section may be provided by a second row that is adjacent to the first row in the two-dimensional array.

Example 4 is the processing system of Example 1, wherein each multiplier of the plurality of multipliers is to apply a convolution filter element to an input data element.

Example 5 is the processing system of Example 1, wherein the convolver unit may further comprise a subsampling circuit to perform at least one of: averaging a plurality of convolution results or determining a maximum value of convolution results.

Example 6 is the processing system of Example 1, wherein the convolver unit may further comprise a plurality of multiplexers, each multiplexer to select one of: a first latch output, a second latch output, or an external memory input to be supplied to a multiplier.

Example 7 is the processing system of Example 1, wherein the convolution filter may be provided by a rectangular matrix of pre-defined binary values; and wherein each set of latches may comprise a number of latches which is equal to a dimension of the convolution filter.

Example 8 is the processing system of Example 1, wherein a latch of the first plurality of latches is connected in series with a latch of a second plurality of latches.

Example 9 is a method, comprising: setting, by a processing device, an initial position of an input window in a two-dimensional array of input data elements; applying a convolution filter to a plurality of input data elements referenced by the input window; shifting the input window, relatively to its previous position, by one or more positions along a one-dimensional section of the two-dimensional array; and iteratively repeating the applying and shifting operations for a pre-defined number of times, wherein at least one of the applying operations comprises receiving an input data element from one of: an external memory or an internal latch of two or more sets of latches, each set of latches corresponding to a respective one-dimensional section of the two-dimensional array.

Example 10 is the method of Example 9, wherein the applying and shifting operations may comprise: applying a convolution filter to a first plurality of input data elements referenced by the input window; shifting the input window, relatively to its previous position, by one position along a first one-dimensional section of the two-dimensional array; applying the convolution filter to a second plurality of input data elements referenced by the input window; shifting the input window, relatively to the initial position, by one position along a second one-dimensional section of the two-dimensional array; and applying the convolution filter to a third plurality of input data elements referenced by the input window; shifting the input window, relatively to its previous position, by one position along a first one-dimensional section of the two-dimensional array; and applying the convolution filter to a fourth plurality of input data elements referenced by the input window.

Example 11 is the method of Example 10, further comprising: repeating, a pre-defined number of times, at least one of sequences of the shifting and applying operations, wherein the number of times is determined as a pooling sample dimension reduced by one.

Example 12 is the method of Example 9, wherein the first one-dimensional section may be provided by a first row the and second one-dimensional section may be provided by a second row that is adjacent to the first row in the two-dimensional array.

Example 13 is the method of Example 9, further comprising: performing a subsampling operation of convolution operation results.

Example 14 is the method of Example 9, wherein the receiving further comprises storing the input data element in an internal latch.

Example 15 is an apparatus, comprising: a memory; a processing system coupled to the memory, the processing system to perform the method of any of the examples 9-14.

Example 16 is a system-on-chip (SoC), comprising: a plurality of convolver units, each convolver unit to apply a convolution filter to a plurality of input data elements represented by a two-dimensional array, each convolver unit comprising a plurality of multipliers coupled to two or more sets of latches, wherein each set of latches is to store a plurality of data elements of a respective one-dimensional section of the two-dimensional array.

Example 17 is the SoC of Example 16, wherein the two or more sets of latches may be provided by a first set of latches and a second set of latches, wherein the first set of latches is to store a first plurality of data elements of a first one-dimensional section of the two-dimensional array and the second set of latches is to store a second plurality of data elements of a second one-dimensional section of the two-dimensional array.

Example 18 is the SoC of Example 16, wherein the first one-dimensional section may be provided by a first row the and second one-dimensional section may be provided by a second row that is adjacent to the first row in the two-dimensional array.

Example 19 is the SoC of Example 16, wherein each multiplier is to apply a convolution filter element to an input data element.

Example 20 is the SoC of Example 16, further comprising a subsampling circuit to perform at least one of: averaging a plurality of convolution results or determining a maximum value of convolution results.

Example 21 is the SoC of Example 16, wherein each convolver unit may further comprise a plurality of multiplexers, each multiplexer to select one of: a first latch output, a second latch output, or an external memory input to be supplied to a multiplier.

Example 22 is the SoC of Example 16, wherein the convolution filter may be provided by a rectangular matrix of pre-defined binary values; and wherein each set of latches may comprise a number of latches which is equal to a dimension of the convolution filter.

Example 23 is the SoC of Example 16, wherein a latch of the first plurality of latches is connected in series with a latch of a second plurality of latches.

Example 24 is a computer-readable non-transitory storage medium comprising executable instructions that, when executed by a processing system comprising a plurality of processing cores, cause the processing system to perform operations, comprising: setting an initial position of an input window in a two-dimensional array of input data elements; applying a convolution filter to a plurality of input data elements referenced by the input window; shifting the input window, relatively to its previous position, by one or more positions along a one-dimensional section of the two-dimensional array; and iteratively repeating the applying and shifting operations for a pre-defined number of times, wherein at least one of the applying operations comprises receiving an input data element from one of: an external memory or an internal latch of two or more sets of latches, each set of latches corresponding to a respective one-dimensional section of the two-dimensional array.

Example 25 is the computer-readable non-transitory storage medium of Example 24, wherein the applying and shifting operations may comprise: applying a convolution filter to a first plurality of input data elements referenced by the input window; shifting the input window, relatively to its previous position, by one position along a first one-dimensional section of the two-dimensional array; applying the convolution filter to a second plurality of input data elements referenced by the input window; shifting the input window, relatively to the initial position, by one position along a second one-dimensional section of the two-dimensional array; applying the convolution filter to a third plurality of input data elements referenced by the input window; shifting the input window, relatively to its previous position, by one position along a first one-dimensional section of the two-dimensional array; and applying the convolution filter to a fourth plurality of input data elements referenced by the input window.

Example 26 is the computer-readable non-transitory storage medium of Example 24, further comprising executable instructions causing the processing system to perform operations, comprising: repeating, a pre-defined number of times, at least one of sequences of the shifting and applying operations, wherein the number of times is determined as a pooling sample dimension reduced by one.

Example 27 is the computer-readable non-transitory storage medium of Example 24, wherein the first one-dimensional section may be provided by a first row the and second one-dimensional section may be provided by a second row that is adjacent to the first row in the two-dimensional array.

Example 28 is the computer-readable non-transitory storage medium of Example 24, further comprising executable instructions causing the processing system to perform operations, comprising: performing a sub sampling operation of convolution operation results.

Example 29 is the computer-readable non-transitory storage medium of Example 24, wherein the receiving further comprises storing the input data element in an internal latch.

Some portions of the detailed description are presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the means used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here and generally, conceived to be a self-consistent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, transferred, combined, compared and otherwise manipulated. It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers or the like.

It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. Unless specifically stated otherwise as apparent from the above discussion, it is appreciated that throughout the description, discussions utilizing terms such as “encrypting,” “decrypting,” “storing,” “providing,” “deriving,” “obtaining,” “receiving,” “authenticating,” “deleting,” “executing,” “requesting,” “communicating,” or the like, refer to the actions and processes of a computing system, or similar electronic computing device, that manipulates and transforms data represented as physical (e.g., electronic) quantities within the computing system's registers and memories into other data similarly represented as physical quantities within the computing system memories or registers or other such information storage, transmission or display devices.

The words “example” or “exemplary” are used herein to mean serving as an example, instance or illustration. Any aspect or design described herein as “example” or “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects or designs. Rather, use of the words “example” or “exemplary” is intended to present concepts in a concrete fashion. As used in this application, the term “or” is intended to mean an inclusive “or” rather than an exclusive “or.” That is, unless specified otherwise, or clear from context, “X includes A or B” is intended to mean any of the natural inclusive permutations. That is, if X includes A; X includes B; or X includes both A and B, then “X includes A or B” is satisfied under any of the foregoing instances. In addition, the articles “a” and “an” as used in this application and the appended claims should generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. Moreover, use of the term “an embodiment” or “one embodiment” or “an implementation” or “one implementation” throughout is not intended to mean the same embodiment or implementation unless described as such. Also, the terms “first,” “second,” “third,” “fourth,” etc. as used herein are meant as labels to distinguish among different elements and may not necessarily have an ordinal meaning according to their numerical designation.

Embodiments descried herein may also relate to an apparatus for performing the operations herein. This apparatus may be specially constructed for the required purposes, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in the computer. Such a computer program may be stored in a non-transitory computer-readable storage medium, such as, but not limited to, any type of disk including floppy disks, optical disks, CD-ROMs and magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, flash memory, or any type of media suitable for storing electronic instructions. The term “computer-readable storage medium” should be taken to include a single medium or multiple media (e.g., a centralized or distributed database and/or associated caches and servers) that store the one or more sets of instructions. The term “computer-readable medium” shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by the machine and that causes the machine to perform any one or more of the methodologies of the present embodiments. The term “computer-readable storage medium” shall accordingly be taken to include, but not be limited to, solid-state memories, optical media, magnetic media, any medium that is capable of storing a set of instructions for execution by the machine and that causes the machine to perform any one or more of the methodologies of the present embodiments.

The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general-purpose systems may be used with programs in accordance with the teachings herein, or it may prove convenient to construct a more specialized apparatus to perform the required method operations. The required structure for a variety of these systems will appear from the description below. In addition, the present embodiments are not described with reference to any particular programming language. It will be appreciated that a variety of programming languages may be used to implement the teachings of the embodiments as described herein.

The above description sets forth numerous specific details such as examples of specific systems, components, methods and so forth, in order to provide a good understanding of several embodiments. It will be apparent to one skilled in the art, however, that at least some embodiments may be practiced without these specific details. In other instances, well-known components or methods are not described in detail or are presented in simple block diagram format in order to avoid unnecessarily obscuring the present embodiments. Thus, the specific details set forth above are merely exemplary. Particular implementations may vary from these exemplary details and still be contemplated to be within the scope of the present embodiments.

It is to be understood that the above description is intended to be illustrative and not restrictive. Many other embodiments will be apparent to those of skill in the art upon reading and understanding the above description. The scope of the present embodiments should, therefore, be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. 

What is claimed is:
 1. An apparatus, comprising: a first convolution circuit to apply a first filter to a first input image to obtain a first output image of an equal or smaller size; a second convolution circuit to apply a second filter to a second input image to obtain a second output image of an equal or smaller size; a pooling circuit coupled to outputs of the first and second convolution circuits to perform a subsampling operation by averaging the first and second output images.
 2. The apparatus of claim 1, wherein the first and second filters are convolution filters.
 3. The apparatus of claim 1, wherein the first and second convolution circuits comprise: a plurality of multipliers coupled to two or more sets of latches, wherein each set of latches is to store a plurality of data elements of a respective one-dimensional section of the two-dimensional array.
 4. The apparatus of claim 3, wherein the two or more sets of latches are provided by a first set of latches and a second set of latches, wherein the first set of latches is to store a first plurality of data elements of a first one-dimensional section of the two dimensional array and the second set of latches is to store a second plurality of data elements of a second one-dimensional section of the two-dimensional array.
 5. The apparatus of claim 3, wherein each multiplier of the plurality of multipliers is to apply a convolution filter element to an input data element.
 6. The apparatus of claim 3, wherein the first and second convolution circuits comprise a plurality of multiplexers, each multiplexer to select one of: a first latch output, a second latch output, or an external memory input to be supplied to a multiplier.
 7. The apparatus of claim 3, wherein the first and second convolution circuits further comprise adders to sum the multiplication results.
 8. The apparatus of claim 1, wherein the pooling circuit is to add the first and second output images prior to performing the subsampling operation.
 9. The apparatus of claim 1, further comprising: a plurality of convolution circuits to apply filters to input images, wherein a total number of convolution circuits in the apparatus is equal to a size of the first filter.
 10. The apparatus of claim 1, further comprising: a classification layer coupled to the pooling circuit to classify the convolved and pooled images.
 11. A method, comprising: applying a convolution filter to a plurality of input data elements of a multi-dimensional array according to an input window to generate a result; shifting the input window, relatively to its previous position, by one or more positions along a one-dimensional section of a multi-dimensional array; and iteratively repeating the applying a convolution filter and shifting the input window, wherein at least one of the applying comprises receiving an input data element from one of: an external memory or an internal latch of two or more sets of latches, each set of latches corresponding to a respective one-dimensional section of the two-dimensional array.
 12. The method of claim 11, wherein a first one-dimensional section is provided by a first row and a second one-dimensional section is provided by a second row that is adjacent to the first row in the multi-dimensional array.
 13. The method of claim 11, further comprising: performing a subsampling of convolution results.
 14. The method of claim 12, further comprising: adding the convolution results prior to subsampling.
 15. The method of claim 11, further comprising: receiving the plurality of input data elements from memory. 